package 牛客网_N.动态规划.机器人走方格1_1;

import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner in = new Scanner(System.in);
		String str = in.nextLine();
		String[] dataStr = str.split(" ");
		int x = Integer.parseInt(dataStr[0]);
		int y = Integer.parseInt(dataStr[1]);
		int	[][] dp = new int[13][13];
		dp[1][1] = 1;
		for(int i = 2; i <= x; i++){
			dp[i][1] = dp[i-1][1];
		}
		for(int j = 2; j <= y; j++){
			dp[1][j] = dp[1][j-1];
		}
		for(int i = 2; i <= x; i++){
			for(int j = 2; j <= y; j++){
				dp[i][j] = dp[i-1][j] + dp[i][j-1];
			}
		}
		System.out.println(dp[x][y]);
	}
}
